forked from unom/punktfunk
enricobuehler
4f8cce6751
767e67ca's per-channel mechanics were correct; they were aimed at the wrong binary. Each one is restored here pointed at punktfunk-encode-worker, and every host-side removal from #136 stays verbatim. All grants remain best-effort — an uncapped worker still encodes, at default priority, so a failed setcap must never fail an install. * Arch: setcap in post_install AND post_upgrade (a replaced binary is a new inode). * RPM: %caps(cap_sys_nice=ep) in %files, never a %post setcap — %caps applies, restores and verifies, and covers Fedora as well as Bazzite via rpm-ostree layering. * Bazzite + Arch sysext: setcap on the staging tree before mksquashfs, which does record security.capability. The assertion is amended, not removed: host EMPTY is still a hard fail, and the worker must carry exactly cap_sys_nice=ep — missing is fine, anything else is not. * deb: setcap in postinst. * NixOS: security.wrappers for the WORKER plus PUNKTFUNK_ENCODE_WORKER in the unit. A file capability cannot live on a store path, and an ambient grant is right here precisely because nothing ever identifies the worker. The host's ExecStart stays on the store path. * Steam Deck: setcap the worker; the .desktop the script writes stays valid this time. Four things the plan's channel table missed: * packaging/arch/build-sysext.sh had no capability handling at all, and a sysext can never run a pacman scriptlet — the SteamOS image would have shipped the lever permanently inert. * scripts/steamdeck/update.sh had none either. It rebuilds both binaries, so a new inode drops the grant, and it is the documented steady-state path: the lever would have died on the first update. It also never healed a Deck already capped by 0.26.0-1. * A capped worker is AT_SECURE, and glibc drops $ORIGIN-expanded RPATH entries for secure binaries unless they normalise into a trusted system dir. Copying the host's rpath under BUNDLE_FFMPEG=1 would have left the capped worker unable to find libavcodec on exactly the channel that bundles it. Absolute DT_RPATH instead. * Nix crane scopes by -p, so the worker would not have been built at all, and it needs its own addDriverRunpath. scripts/ci/assert-cap-matrix.sh mechanizes the lesson from 0.26.0-1 — verify the PACKAGE, never the board. It unpacks the built Arch package, the deb, the rpm and the mounted sysext raw and asserts one matrix: the host carries NOTHING (hard fail), the worker exactly cap_sys_nice=ep. The sysext reader first proves it can round-trip a capability through mksquashfs/unsquashfs at all, so an unreadable artifact fails rather than issuing a blind PASS, and --self-test red-teams the assertions themselves. Red-teaming the leg found a real bug: setcap originally ran BEFORE the assertion, so "the worker arrived carrying something unexpected" was unreachable and a stray %caps would have been silently overwritten. Both sysext scripts now assert, then grant, then assert again.